The present invention relates to a subtraction and charge quantity generation charge transfer device. It also relates to an analog signal processing charge transfer system equipped with such a device.
During the processing of analog signals by charge transfer, it is often necessary to carry out subtraction between two signals. In the prior art, the charges are generally converted into a voltage and the subtraction then takes place on the voltages. A quantity of charges corresponding to the subtraction result is then reinjected into the charge transfer system.
Conversions of charges into voltages and vice versa have the disadvantage of having only limited linearity and having a difficulty reproducible gain. Moreover, the devices used for carrying out conversions and subtractions on voltages are generally cumbersome and have a high current consumption.